Nebraska Sand Hills: the Last Prairie

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln

Proceedings of the North American Prairie Conferences North American Prairie Conference

1989

Nebraska Sand Hills: The Last Prairie

Robert F. Whitcomb Insect Pathology Laboratory, Agricultural Research Service, Beltsville, Maryland

Follow this and additional works at: https://digitalcommons.unl.edu/napcproceedings

Part of the International and Area Studies Commons

Whitcomb, Robert F., "Nebraska Sand Hills: The Last Prairie" (1989). Proceedings of the North American Prairie Conferences. 33. https://digitalcommons.unl.edu/napcproceedings/33

This Article is brought to you for free and open access by the North American Prairie Conference at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Proceedings of the North American Prairie Conferences by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. NEBRASKA SAND HILLS: THE LAST PRAIRIE

Robert F. Whitcomb Insect Pathology Laboratory, Agricultural Research Service, Beltsville, Maryland 20705

Abstract. Although North American grasslands are diverse and biotically conducted on the ecology and evolution of leafhoppers of North rich, their conservation has never received high priority. As a result, the American grasslands. These studies pointed out both the signifi­ prairie landscape has all but disappeared. However, one prairie region has cance of the Sand Hills and the need to make their importance retained its essential pre-Columbian features. This is the Nebraska Sand known to others. Hills Prairie, a 4.8 million ha stabilized dune region of Holocene origin. At the time of European settlement of the New World, the North Because the Sand Hills lie at the heart of the North American grasslands, their biota is influenced by the adjacent short- and tallgrass prairies and American continent was rich in both mesic and semiarid grass­ by northern (cool-season) and southern (warm-season) grasslands. In ad­ lands. Today, the mesic grasslands that constituted the true prairie dition, the Sand Hills have their own distinctive sand-dependent biota. have been largely turned over to intensive agriculture. The Ne­ Equally important, however, is the heritage conveyed by their uninterrupted braska Sand Hills Prairie (Pool 1914, Keech and Bentall 1978, landscape and rich cultural history. Although the Sand Hills could be Wolfe 1984, Bleed and Flowerday 1989) is a 4.8 million ha region threatened by turning of their erodible soils for agronomic purposes that which has not declined in condition since European settlement. If are not sustainable in the long term, implementation of the Conservation landscape as well as grass is considered, the Nebraska Sand Hills Reserve Program has reinforced historic patterns of sound land manage­ is the last prairie. To relate the significance of the Sand Hills to ment. As a result, privately managed land in the Sand Hills serves a others, this paper has been organized first to describe the ecosystem conservation function of global significance. In this region the optimal long-term public and private land use appears to be native prairie. and then to address the issue of conservation. Key Words. Sandhills, prairie, Nebraska, preservation. DISCUSSION

INTRODUCTION Nebraska Sand Hills: The Heart of the North American Grasslands The grassland types of the United States were mapped by Ki.i­ "The ranchman understood and loved the land the way chler (1964 and 1985). This work defined a "potential vegetation" he found it - grass side up. He knew, even as the Indian in which vegetation was classified in terms of the natural com­ knew, that much of it could not be profitably farmed, munities that dominated the landscape before European settlement that to break its thin, root-bound skin would deface and and that would reassert dominance in the absence of human dis­ ruin it for years to come" turbance. In addition to grasslands, of which 44 were described, Nellie Snyder Yost several other formations were described, such as juniper-pinyon and ponderosa pine forests, which are in fact preponderantly grass­ This paper has its foundations in a series of studies (Whitcomb land. The Nebraska Sand Hills lie at the heart of these North etal. 1986, 1987, and 1988, Whitcomb and Hicks 1988) that were American grasslands (Figure 1).

FIG. 1. Grassland regions of the United States; modified from Ki.ichler (1964 and 1985). The Nebraska Sand Hills Prairie (solid black) lies at the heart of the North American grasslands (modified from Whitcomb et al. 1987); see this publication for descriptions· of the illustrated regions.

PROCEEDINGS OF THE ELEVENTH NORTH AMERICAN PRAIRIE CONFERENCE 1989 57 58 PROCEEDINGS OF THE ELEVENTH NORTH AMERICAN PRAIRIE CONFERENCE

East of the Sand Hills, wherever terrain pennitted, the prairie from distant source areas, alluvial sands originated in regions im­ has been almost quantitatively converted into cropland. Regions mediately to the west of the Sand Hills. For example, material of that were originally true prairie, or mosaics of prairie and wood­ the White River Group probably are derived in large part from land, generally receive 500 or more mm of annual precipitation, what is now Colorado. Even in the early Tertiary, alluvial sands a reasonable proportion of which falls during the growing season. had begun to accumulate in the present-day Sand Hills region. A These prairies were dominated by tall grasses, including many paleovalley of the White River Group with as much as 15 m of wann-season (C4 ) species. Principal dominant grasses of this re­ Chadron Fonnation sand occurs under most of Garden County gion include big bluestem (Andropogon gerardii Vitman), little (Swinehart and Diffendal 1989). The Arikaree group, fonned 28- bluestem (Andropogon scoparius Michx.), indiangrass [Sorghas­ 19 million YBP, covers the western third of the Sand Hills. One trum nutans (L.) Nash], and switchgrass (Panicum virgatum L.). Arikaree paleovalley, as wide as 40 km in some places, is filled The regions in which these grasses were dominant include tall­ with more than 61 m of fine to medium sand. grass prairie, oak savanna, deciduous forest-prairie mosaic, and the Fayette and Blackland Prairies of Texas. South of the Sand Hills, the mixed prairie is a transitional grass­ land composed largely of short and tall wann-season grasses; this prairie fonnation receives 380-500 mm of annual precipitation. In this region, buffalograss [Buchloe dactyloides (Nutt.) Engelm.] and blue grama [Bouteloua gracilis (Willd. ex H. B. K.) Lag. ex Griffiths] assume considerable importance. North of the Sand Hills, the transitional region between mesic and dry grassland is domi­ nated by cool-season grasses such as western wheatgrass (Agro­ pyron smithii Rydb.) and prairie junegrass [Koeleria pyramidata (Lam.) Beauv.]. Northwest of the Sand Hills, the semiarid prairie, although containing a minor component of short, warm-season grasses (blue grama and buffalograss) is largely a wheatgrass (Agropyron) prairie. To the west and southwest of the Sand Hills, the semiarid short-grass prairie, which receives 250-380 mm of annual precipitation, is dominated by blue grama and buffalograss. With these different influences, it is small wonder that the Sand Hills have a biotic diversity that would not be predicted from their apparently monotonous physiognomy. This would be so, even if they were not composed of a seemingly infinite variety of com­ binations of sand and soil and water distributed along latitudinal and elevational gradients. Climate Twb The Sand Hills region is large enough to exhibit considerable climatic variation. Annual precipitation in the Sand Hills ranges ...... 1<' '. : from about 580 mm in the east to less than 430 mm in the west .. : .. P. .. (Wilhite and Hubbard 1989). As much as half of the precipitation I' • ' •• is received during the prime growing season from May through July. Mean precipitation values for the Sand Hills can be deceiving, since precipitation varies greatly from year to year. For example, long-tenn records for Ewing, Nebraska show annual precipitation from as high as 960 mm to as low as 320 mm, the latter occurring in the 1936 drought. The Sand Hills were affected by the "great Kc drought" of the 1930s, but they suffered less than many other Great Plains regions largely because the native flora is well adapted to withstand such variations in precipitation. Also, droughts, al­ though severe, were of short enough duration that they did not severely affect the groundwater reserves. Snowfall, which ranges from 560 mm in the south to 1,440 mm in the north, is an important factor in groundwater recharge. Mean temperatures in the Sand Hills range from 20-25 C. The FIG. 2. Geologic section, west to east, of Grant County in the freeze-free season varies from 150 days in the east to 120 in the west central Sand Hills. Vertical exaggeration of diagram causes west, primarily a reflection of elevational differences (approxi­ slopes to appear steeper than they actually are. Designations: Qe mately 1,220 m in the west to about 610 m in the east). Prevailing = Eolian sand of Holocene origin; QTa = Alluvial sand and silt winds usually have a westerly component but frequently also are of Quaternary and/or Pliocene origin; To = Ogallala Group (Mio­ northerly or southerly; east winds are uncommon (Wilhite and cene); Ta = Arikaree Group (Miocene and Oligocene); Twb and Hubbard 1989). Twc = Brule fonnation and Chadron fonnation (respectively) of the White River Group (Oligocene); Kp and Kc = Pierre Shale Geology and Soils and Colorado Group (respectively) of the Upper Cretaceous; and About 98 million years before present (YBP), the present-day Kd = Dakota Group of the Lower Cretaceous. Two oil and gas area of the Sand Hills was covered by Cretaceous seas (Swinehart tests are diagrammed: the end of the cased zone is indicated by a and Diffendal 1989). Sediments of these seas were deposited for short horizontal line . Two faults are also diagrammed: arrows show about 33 million years, until sea level fell worldwide. The Cen­ direction of relative movement. Modified from a geologic section ozoic strata found today between the recently deposited eolian of the entire Sand Hills region of Swinehart and Diffendal (1989). (wind-deposited) sand and the underlying Jurassic and Cretaceous strata consist of either fine-grained volcanic sediments or alluvial sediments (Figure 2). Whereas the volcanic sediments originated NEBRASKA SAND HIllS: THE LAST PRAIRIE 59

Beginning about 19 million YBP, in the Miocene, Ogallala group Valley. Also, Swinehart and Diffendal (1989) believe that the mod­ sediments began to accumulate in a major sedimentary basin (Fig­ ern Dismal River valley is less than 1,500 years old. ure 2). The drainage systems of this basin were diffuse. Ogallala But the current major geologic feature of the Sand Hills region sediments may have been deposited as alluvial fans or as sediments is its stabilized eolian sand (Figure 2). In the south central and of braided rivers in wide shallow valleys. Thus, this group may west central Sand Hills it is common to find 9-18 m of eolian sand; represent an alluvial plain with a complex history (Swinehart and in other areas the thickness is 1-9 m. The sands contain between Diffendal 1989). Source areas of these sediments include present­ 1 and 4% silt and clay, giving the soils a cohesive property not day Wyoming and Colorado. These areas continued to be sources possessed by pure sand. In many areas, vertical walled trenches of alluvial sand in the Pliocene. Evidence for this is the presence can be dug in the dunes. in the sands of coarse sediments of that age consisting of uncom­ Although the Sand Hills are the largest eolian sand body in the mon materials such as anorthosite, an uncommon igneous rock of western hemisphere, they are smaller than the large unstabilized Wyoming's Laramie Mountains, or quartz pebble conglomerate sand areas of North Africa, Arabia, Asia, and Australia (Wilson, from Wyoming's Snowy Range. 1973). They are, however, one of the largest stabilized sand regions A scarcity of sediments between 2 million and 40,000 YBP in the world. makes assessment of the early Quaternary speculative. It is possible Presumably, eolian activity is at least roughly correlated with that significant erosion of the Ogallala and overlying younger strata dry climatic conditions. Large dunes tend to form in sandy regions occurred during the Pleistocene. when vegetation cover is less than 20% (Swinehart 1989). Under Modern drainage systems such as the Loup, as well as the current precipitation regimes, cover in the Sand Hills greatly ex­ Calamus and Niobrara (Figure 3), began to form about 20,000 ceeds this percentage. Although some modern sand seas have less YBP at the time of the last major pulse of continental glaciation. than 100 mm of annual precipitation, the Sand Hills may have At that time, the area of today's Sand Hills may have been a broad developed with annual precipitation of nearly 250 mm per year alluvial plain with sandy streams flowing in valleys of low relief. (Swinehart 1989). Voorhies and Cormer (1985), for example, estimate that the central Although not obvious at the ground level, there are strong pat­ Niobrara valley during this period was 2-3 times wider but only terns in the arrays of large and small dunes. For example, satellite half as deep as the modem Niobrara River. images of the west-central Sand Hills show strong alignments of Dramatic changes in the Great Plains region occurred 12,000 straight to slightly curved ridges, with long axes trending west to YBP as the last continental ice sheets retreated. By 9,000 YBP, east (Swinehart et ai. 1989). spruce forests with prairie inclusions and aspen-pine parklands had Further, the dunes of the Sand Hills have many forms (Smith given way to prairie (Fredlund and Jaumann 1987). But even 1965, Swinehart 1989). Parabolic dunes develop a "U" or "V" during the Holocene, Sand Hills drainage patterns experienced shape because their arms are anchored by vegetation. These dunes, dynamic changes. May and Holen (1985), for example, docu­ essentially confined to the southwestern Sand Hills, have a con­ mented five distinct Holocene alluvial fills in the South Loup sistent southeastern orientation. Dune-forming winds must, there-

SCALE 20 eo • H !

FIG. 3. The Sand Hills region of Nebraska (shaded). Kinkaid Counties (see text: European Colonization) lie to the west of the broad dashed line. A small portion of the Sand Hills extends into southern South Dakota. 60 PROCEEDINGS OF THE ELEVENTH NORTH AMERICAN PRAIRIE CONFERENCE fore, have blown from the northwest. In northeastern Colorado ha, probably formed at this time. Ahlbrandt et al. (1983) hypoth­ (Ramaley 1939) and southwestern Nebraska, the presence of dunes esized that larger dunes occurred 8,000 to 5,000 YBP during the similar in age to the Sand Hills indicate that winds there must also middle Holocene warm and dry period (altithermal) (Barry 1983). have blown predominantly from the northwest (Muhs 1985) (Fig­ Corroborative evidence for Holocene origin of the Sand Hills has ure 4). now come from many other sources (Bleed and Flowerday 1989). Most of the dunes have blowouts which, on a landscape level, For example, Muhs (1985) found only immature soil profiles on impart a dimpled or pockmarked texture to large areas of the dune Sand Hills dunes with thin A horizons that contain little organic system. Pool (1914) described the cycle by which these depressions matter (Lewis 1989). Even in soils of sub irrigated meadows with are generated and, eventually, revegetated. Blowouts originate on thick A horizons, subsoils are unstructured and show no signs of exposed upper slopes where the cover is broken or depleted from clay accumulation. Thus, it appears that Sand Hills soils are in disturbances such as fire or overgrazing. During early stages, the early stages of development. Many may be no more than 1,500 blowout is simply a patch of bare sand a few meters wide and a years old. few centimeters deep. Roots of deeper-rooted plants are exposed All available evidence, therefore, favors creation of the Sand by the wind and, in time, the entire plant is blown away. When Hills during multiple episodes of eolian activity during the last the young blowout is no more than 4-5 cm in depth the sand begins 10,000 years. Because these episodes were asynchronous, the dune to slide into the depression, from which it is then blown away. fields have a complex history (Bradbury 1980). Present day eolian After a number of years, the blowout may be hundreds of meters activity in the Great Sand Dunes area of south-central Colorado, across. The inner slope that faces the wind is long and extensive. in contrast to the pattern of stabilization in the Sand Hills, is a The opposite side is much steeper, in some cases nearly perpen­ current example of such complexity and demonstrates that eolian dicular. The steepness of this slope is often maintained by growth activity is not necessarily correlated with contemporary climate. of sand-colonizing plants that are sheltered from the wind by the Nevertheless, it is reasonable to infer that appearance of the large lee side of the blowout. Eventually the blowout reaches a size dunes was related to the altithermal. Following about 2,000 yrs from which sand is no longer blown. Instead, the sand slides to of stabilization, the climate again became dry, permitting further the bottom of the blowout and remains there. At the bottom of eolian activity. Extensive modification of crescentic dunes to such blowouts, numerous seeds, carried like the sand to the bottom, domelike and domal-ridge dunes may have taken place in the are able to germinate. The revegetation process initiated in this central and eastern portion of the dune field at this time (Swinehart, way eventually reclaims the blowout. The plant assemblages of 1989). After this eolian activity ceased, about 1,500 YBP, minor blowouts are the most distinctive of the Sand Hills (Tolstead 1942) periods of drought have occurred, during which blowout processes and include blowout grass [Redfieldia flexuosa (Thurb.) Vasey] have modified local dune structures (Swinehart 1989). and the endemic blowout penstemon (Penstemon haydenii S. Wats.). The source of the Sand Hills sand is indicated clearly by the At one time, it was believed that the Sand Hills dated to the geologic nature of its underlying sediments. As much as 60 m of Pleistocene (Lugn 1935, Swinehart 1989). However, Ahlbrandt et Pliocene and Quaternary alluvial sand underlies the southeastern al. (1983) studied 7 sites at which radiocarbon-dated material less Sand Hills, and Quaternary sands are widespread in the northwest. than 10,000 years old was overlain by eolian sand. The best doc­ The sand worked by Holocene eolian activity was derived, there­ umented interval of activity occurred 3,500 to 1,500 YBP. The fore, simply from unconsolidated alluvial sands that covered most linear dunes and most of the sand sheets, totalling about 2.1 million of the present area of the Sand Hills during the early Holocene (Swinehart 1989).

SOUTH DAKOTA

Casper Dunes QC=C>~ K illpecker

o lOa MILES I ! o lOa I(ILOMETERS L---..J Dune field Primary direction of sand transport

FIG. 4. Archipelago of sand regions in the west central Great Plains and central Rocky Mountain states. Figure from Ahlbrant et al. (1983) as modified by Swinehart (1989) NEBRASKA SAND HIllS: THE LAST PRAIRIE 61

Water Resources Harrison 1980, Kaul 1989). Kaul (1989) recognized 10 general The Sand Hills are underlain by the High Plains Aquifer (Bleed types of vegetational community: bunchgrass, sand muhly, blow­ 1989). Although the thickness of this aquifer (from 60-270 m) outs and draws, needle-and-thread, three-awn grass, short-grass, varies greatly, the portion underlying the Sand Hills is generally meadow, wet meadow, marsh, and aquatic. Sand Hills grasses can thicker than in other plains regions. The principal groundwater also be classified, more or less, on the basis of their adaptedness reservoir of the Sand Hills generally coincides with the base of for soil sandiness, soil moisture, and/or alkalinity (Table 1). Par­ the Ogallala Group. The aquifer generally slopes downward to the ticularly in a region such as the Sand Hills, where plant densities east, an orientation that coincides with the overall direction of the on many sites are relatively low (Pool, 1914), such a classification regional groundwater flow pattern. In some parts of the Sand Hills, may be more appropriate than one based on community member­ the water table is at or near the surface, forming lakes, marshes, ship. and subirrigated meadows. A unique set of conditions is responsible for the rich groundwater resources of the Sand Hills. Although precipitation is only mod­ Table 1. Diagrammatic representation of the grasses of the Sand Hills erate and evapotranspiration rates are high, the combination of ordinated by their position on the moisture gradient (vertical axis), thick deposits of consolidated and gravelly sands, together with soil sandiness (horizontal axis, upper portion of table) and water highly permeable surface sands, produces ideal conditions for aqui­ alkalinity (horizontal axis, lower portion). fer recharge. Groundwater sequestered under such circumstances is mostly very low in dissolved solids. More sandy Less sandy The groundwater reserves of the Sand Hills are of national significance (Bleed 1989). Overflow from the aquifer feeds the RedJieldia Jlexuosa Niobrara River and other streams and rivers. And, because the Muhlenbergia pungens water is an important component of the Platte system, it is an Triplasis purpurea important resource for downstream regions. Although large, this Calamovilfa longifolia Bouteloua hirsuta water resource is also fragile. Therefore, in areas where ground­ Buchloe dactyloides water is close to the surface, extensive pumping could lower local Koeleria pyrimidata water tables, severely impacting wetland ecosystems. High soil Bouteloua gracilis permeability, which facilitates recharge, would also facilitate Bouteloua curtipendula groundwater contamination if pesticides or fertilizers were used Stipa comata on a large scale. Control of infiltration of such contaminants into Stipa viridula the groundwater would be very difficult. For such reasons, the Andropogon scoparius water resources of the Sand Hills require careful management Muhlenbergia cuspidata (Bleed 1989). Sporobolus cryptandrus Much of the western third of the region lacks streams and is Agropyron smithii referred to as the "Closed Basins Area" (Figure 3). The Niobrara Aristida purpurea river, whose headwaters are in eastern Wyoming, is the only Sand Paspalum setaceum Hills river that originates outside the region. Other drainage sys­ Dichanthelium oligosanthes tems originate in the hills themselves. Since these streams are Dichanthelium acuminata largely derived from relatively steady groundwater seepage, they Dichanthelium wilcoxianum have a nearly constant discharge rate (Bentall 1989). Eragrostis spectabilis In general, Sand Hills lakes (Bleed and Ginsberg 1989) tend to Andropogon hall;; be at least slightly alkaline. One of the lakes is among the most Eragrostis trichodes alkaline natural inland bodies of water known. Some lakes are Poa pratensis also hypersaline. Elymus canadensis Elymus virginicus Flora Sorghastrum nutans The plant species composition of the Sand Hills suggests that Andropogon gerard;; their flora has been recruited largely from the surrounding prairie. Blowout or Hayden's penstemon is an exception to a rule of rel­ Mesic atively low plant endemism. It is likely, given the Holocene origin of the Sand Hills and repeated subsequent pulses of eolian activity Sporobolus airoides in the region (Ahlbrandt and Fryberger 1980, Ahlbrandt et al. Hordeum jubatum 1983, Swinehart 1989), that changes in the Sand Hills biota have Agrostis stolonifera been extensive and dynamic. In addition, an archipelago of smaller Puccinellia nutalliana sand regions (Fig. 4) in the plains and Rocky Mountain regions Distichlis spicata (Ahlbrandt et al. 1983, Swinehart 1989) has supplied an extensive, Muhlenbergia asperiJolia although fragmented, sand substrate. Hence, the present sand flora, Sphenopholis obtusata and its associated fauna, may have been widely distributed during Spartina gracilis the Holocene. Spartina peetinata Of about 700 plant species recorded from the Sand Hills, only Leersia oryzoides about 50 are introduced. This number of exotic species is re­ Polypogon monspeliensis markably low for an area so large. In contrast, Kaul and Rolfsmaier Alopecurus aequalis (1987), while cataloging 300 native species on a tallgrass prairie Phalaris arundinacea of about 100 ha near Lincoln, also cataloged 60 introduced species. Phragmites australis Further, most of the introduced Sand Hills plant species occur in Glyceria striata disturbed areas such as roadsides, cultivated fields, and heavily Glyceria grandis grazed rangeland, which constitute a small fraction of the total Catabrosa aquatiea Sand Hills area. Beckmannia syzigachne The Sand Hills Prairie, especially on xeric and mesic sites, is Hydric dominated by grasses (Sutherland 1984). There have been nu­ ------merous efforts to group these grasses, and associated forbs, into More alkaline Less alkaline communities (Pound and Clements 1900, Pool 1914, Weaver 1965, 62 PROCEEDINGS OF THE ELEVENTH NORTH AMERICAN PRAIRIE CONFERENCE

Kaul (1989) has listed some of the important Sand Hills forbs (Agropyron smithii Rydb.) or needlegrasses (Stipa spp.). The sea­ and the communities in which they occur. Common forbs in xeric sonal growth flush of these grasses occurs in the spring, when the communities include Arkansas rose (Rosa arkansana Porter), Bush subsurface moisture content of the interdunal soils is high. morning glory (Ipomoea leptophylla Torr.), leadplant (Amorpha Communities on north-facing slopes are often substantially dif­ canescens Pursh), lemon scurfpea (Psora lea lanceolata Pursh), ferent from those on south-facing slopes (Bragg 1978). Bames New Jersey tea [Ceanothus herbaceus Raf. var. pubescens (T. & (1980) felt that the temporal and spatial distribution of available G.) Shinners], penstemon species (including the endemic blowout water along local elevational gradients in the Sand Hills controlled penstemon), pincushion cactus [Coryphanta vivipara (Nutt.) Britt. such species differences through interactions with rooting mor­ & Rose], poison ivy (Toxicodendron rydbergii (Small) Greene], phology, photosynthetic physiology, and transpirational water loss. and sand cherry [Prunus pumila var. besseyi (Bailey) G!.]. In Competitive interactions also may play a role in the local distri­ addition, various composites, such as asters (Aster spp. and sun­ bution of Sand Hills grasses. For example, Heinisch (1981) dem­ flowers (Helianthus spp.) occur in these communities. onstrated the role of root morphology in the niche partitioning of In marshes, wet meadows, and aquatic habitats, a variety of blue grama and hairy grama (Bouteloua hirsuta Lag.) in the west­ sedges, rushes, bulrushes, and reed species are found, as well as ern Sand Hills. such forbs as arrowheads (Sagittaria spp.), clammy-weed [Polan­ Sand Hills communities react dynamically to grazing pressures isia dodecandra (L.) DC subsp. trachysperma (T. & G.) lItis], and fire disturbance and variations in precipitation. Responses to cow lily [Nuphar luteum (L.) Sibth. & Small], duckweeds (Lemna grazing pressure are rarely neutral. Plant species tend to either spp.), floating azolla (Azolla mexicana Pres!.). giant duckweed increase or decrease when grazed (Frolik and Shepherd 1940, [Spirodela polyrhiza (L.) Schleid.], homed pondweed (Zanni­ Brinegar and Keim 1942, Sylvester 1957, Burzlaff 1962, Wolfe chellia palustris L.), water milfoil (Myriophyllum spp.) naiad (Na­ 1973, Bragg 1978, Stubbendieck 1989). jas spp.), pondweed (Potamogeton spp.), smartweed (Polygonum In earlier times, prairie fires were common (Pool 1914, Wolfe spp.), swamp milkweed (Asclepias incarnata L.), watercress (Nas­ 1973, Richards 1980). Although there have been a few sporadic turtium officinale R. Br.), waterlily (Nymphaea spp.), watermeal attempts to use prescribed burning on the Sand Hills range, fires (Wolffia spp.), waterweed (Elodea spp.), water hemlock (Cicuta have been generally feared by landowners, who believe that they spp.), water plantain (Alisma spp.)., winged pigweed [Cycloloma are destabilizing. Indeed, rich growth flushes of the prairie after atripliciJolium (Spreng.) Coult.], and widgeon grass (Ruppia mar­ fire may be short lived if the new grass is exposed to desiccating itima L. var. occidentalis (S. Wats.) Graebn.] (Great Plains Flora late summer winds before the new growth has had an opportunity Association 1986). to regenerate a protective moisture-retaining thatch (Pool 1914). If the vast majority of dry Sand Hills, wet meadows, and zoned In general, the resulting changes in grassland quality after acci­ aquatic niches seem to be monotonous, the flora of the Sand Hills dental fires have not suggested to land managers that burning would river systems does not. This flora is recruited not only from sur­ be a useful tool in the Sand Hills. In some reserves, however, fire rounding prairie vegetation but from eastern, northern, and western has been used as a tool for increasing the content of fire-tolerant floristic systems as weI!. For example, the vegetation of the Nio­ warm-season grasses at the expense of exotic cool-season grasses brara Valley reflects boreal, arid montane, and eastern deciduous such as Kentucky bluegrass (Poa pratensis L.). forest elements (Kaul et al. 1988, Kaul 1989). Some of these The landowners are among the best ecologists in the Sand Hills. elements are apparently relict populations that have persisted through These range managers, reinforced by specialists of the Soil Con­ the Holocene. servation Service and the University of Nebraska, are among the In general, the Sand Hills region, like much of the arid Great best in North America (Stubbendieck 1989). For this reason, and Plains, is now drier than it was during pluvial periods of the because of the close relationship between ecology and range man­ Pleistocene. Throughout the prairies and Great Plains there has agement, advances in basic ecology will no doubt find their way been a tendency for complete retreat of spruce forests. In more rapidly into management practices in the Sand Hills. recent time, there appears to have been a colonization by ponderosa pine (Pinus ponderosa Laws.) and cedars (Juniperus spp.) (Wells Fauna 1983), largely on scarps that are at least somewhat protected from The Sand Hills fauna is very rich, reflecting eastern and western, fire. In the Sand Hills today, in the absence of periodic fire (now northern, and southern influences. human controlled), there is a tendency for ponderosa pine to ex­ Fish. pand its local range, particularly in the vicinity of scarps (Steinauer More than 75 species of fish have been recorded from the Sand and Bragg 1987). Hills during historic times (Hrabik 1989). Only one species is Plant communities in the Sand Hills, like other communities, presumed lost from the pre-European colonization inventory. In are determined in part by proximate and in part by historical de­ the Sand Hills, as elsewhere, fish diversity increases with increas­ terminants. Because the Sand Hills are recent in origin, there has ing downstream position in the drainage basin. The Niobrara drain­ been little time for development of soil diversity or for stochastic age system, in accord with its general biotic richness, has the accumulation of species. The present-day climax communities are second-highest number of fish species in the entire Missouri River therefore relatively simple in terms of species numbers. basin (Bliss and Schainost 1973). In contrast to streams, Sand Hill Among proximate factors, plant species occurrence is related lakes are less diverse with some playa like and others highly strongly to topography. Although blowout communities have rel­ alkaline. Fewer species of resident fish are adapted to these limiting atively few species, dune communities exceed those of the valleys conditions. and wet swales in species richness (Kaul 1989). The availability of subsurface water may be the most important factor determining Amphibians and reptiles. plant species occurrence. The species richness of the dunes is Twenty seven species of amphibians and reptiles occur in the explained by soil texture. Dune soils are coarse textured and have Sand Hills (Freeman 1989a). little organic matter. Because of the high infiltration rates, sub­ Mammals. surface moisture is readily replenished. In contrast, in drier inter­ In the late Pleistocene, mammoth, mastodon, horse, and camel dunal valleys the soils are more finely textured, and less water were found in the present-day Sand Hills region. By 11,000 YBP, percolates into the soil. These soils hold more water in the spring however, perhaps as a result of climatic change, perhaps because than sandier soils but are depleted by midsummer. Thus, in dry of activities of hunter-gatherers, or perhaps for both reasons, all summers these soils have less available moisture than those of the became extinct. More recently, elk (Cervus elaphus), bison (Bison dunes (Bames and Harrison 1982). Plants of the dune tops are bison), and bighorn sheep (Ovis canadensis) have also been ex­ deep-rooted warm-season (C ) grasses (Bames and Harrison 1982, 4 tirpated. But many species of mammals remain. Bames and Heinisch 1984). The interdunal valleys are often dom­ Of about 81 species of Nebraska mammals, 58 occur in the Sand inated by cool-season (C 3) grasses such as western wheatgrass NEBRASKA SAND HILLS: THE LAST PRAIRIE 63

Hills (Freeman 1989b). This list includes three species that occur Table 2. Breeding bird species of the Nebraska Sand HiUs; an expan­ only in the Niobrara Valley. Moreover, two-thirds of Nebraska sion of lists by Molhoff (1985) and Labedz (1989). Alphabetic cQdes mammal species reach a regional, distributional limit in the state following common name are for (a) occurrence within the Sand HiUs (Jones 1964) with some of these limits occurring in the Sand Hills. (codes before colon) and (b) habitat (codes after colon). Occurrence The Sand Hills, thus, act as a barrier that divides the range of code: T = throughout; N,S,E,W = north, south, east, and west; L = some species. For example, a population of the eastern woodrat local; A = accidental. Habitat: F = forest; H = habitations; L = (Neotoma floridana) that occurs along the Niobrara River is dis­ lakes; M = marsh; P = prairie; R = riparian. * = Status uncertain. junct from the main population to the south. Scientific names may be obtained from American Ornithologists' The occurrence of common species may be divided into two Union (1983). Sand Hills habitat zones, wet and dry. In wet areas are found opossum (Didelphis virginiana), masked shrew (Sorex cinereus), Pied-billed grebe, T:L; Eared grebe, T:L; Western grebe, W:L; short-tailed shrew (Blarina brevicauda), least shrew (Cryptotis Double-crested cormorant, W:L; American bittern, T,M; Least bit­ parva) , eastern mole (Scalopus aquaticus), eastern cottontail rabbit tern, E,M; Great blue heron, T:L,R; Cattle egret, N:L; Green-backed (Sylvilagusfloridanus) , fox squirrel (Sciurus niger), gray fox (Uro­ heron, EN:L,R; Black-crowned night heron, T:L,R; White-faced ibis, cyon cinereoargenteus). and least weasel (Mustela nivalis). In drier LA:L; Trumpeter swan, W:L; Canada goose, T:L; Wood duck, T:L; habitats, desert cottontail (Sylvilagus audubonii), black-tailed jack­ Greenwinged teal, N:L; Mallard, T:L; Northern pintail, T:L; Blue­ rabbit (Lepus californicus), spotted ground squirrel (Spermophilus winged teal, T:L; Cinnamon teal, W:L; Northern shoveler, T:L; Gad­ spilosoma), Ord's kangaroo rat (Dipodomys ordii) , silky pocket wall, T:L; American wigeon, W:L; Canvasback, W:L; Redhead, T:L; mouse (Perognathus flavus) , western harvest mouse (Reithrodon­ Lesser scaup L:L; Ruddy duck, T:L; Turkey vulture, N:P,R; North­ tomys megalotis), and northern grasshopper mouse (Onychomys ern harrier, T:P; Sharp-shinned hawk, N:R; Cooper's hawk·, L:R; leucogaster) occur. In addition, beaver (Castor canadensis) and Swainson's hawk, T:P; Red-tailed hawk, T:R; Ferruginous hawk, coyotes (Canis latrans) are common in the Sand Hills. Raccoons W:P; Golden eagle, L:P; American kestrel, T:R,H; Gray partridge, (Procyon lotor) are common even in the absence of trees, since L:P; Greater prairie chicken, T:P; Sharp-tailed grouse, T:P; Wild tur­ they can den in such habitats as burrows or clumps of cattails. key, N,R; Northern bobwhite, E:P,R; Ring-necked pheasant, T:P,R; Bobcats (Lynx rufus) are uncommon. Pronghorn antelope (Antil­ Virginia rail, T ,M; Sora, T:M; American coot, T:L,M; Piping plover, ocapra americana) have been extirpated from the eastern Sand L:L; Killdeer, T:L,R,H; Black-necked stilt, L,L; American avocet, Hills, but they occur in some western parts. Mule deer (Odocoileus W:L; Willet, N:L; Spotted sandpiper, L:L,R; Upland sandpiper, T,P; hemionus) and white-tailed deer (Odocoileus virginiana) are com­ Long-billed curlew, W:P; Common snipe, N:P; American wood­ mon (Freeman 1989b). cock·, E:R; Wilson's phalarope, T:L; Forster's tern, W:L; Least tern, L:L; Black tern, T:L; Rock dove, T:H; Mourning dove, T:L,P,R,H; Birds. Black-billed cuckoo, T:R; Yellow-billed cuckoo, T:R; Barn owl, T:H; The avifauna of the Sand Hills is spectacular by any standard Common screech owl, T:L,P ,R,H; Great horned owl, T:P ,R,H; Bur­ spectacular (Table 2). Seven special features of the region con­ rowing owl, T:P; Long-eared owl, L:R; Short-eared owl, T:P; North­ tribute to this richness. First, the numerous Sand Hills lakes (Bleed ern saw-whet owl, L:F; Common nighthawk, T:P; Common poorwill, and Ginsberg 1989) serve as refugia for migratory waterfowl. W:P; Whip-poor-will, N:R; Chimney swift, T:H; Belted kingfisher, Second, and even more importantly, these lakes serve as breeding T:L,R; Red-headed woodpecker, T:R,H; Red-bellied woodpecker·, areas for waterfowl, shorebirds, and other water birds. A large E:R,; Downy woodpecker, T:R,H; Hairy woodpecker, T:R; Northern assemblage of breeding bird species are restricted to the vicinity flicker, T:R,H; Western wood pewee, W:P,R; Eastern wood pewee, of the lakes including the eared grebe (Podiceps nigricollis), west­ E:R; Willow flycatcher·, L:P ,R; Eastern phoebe, E:H; Say's phoebe, ern grebe (Aechmophorus occidentalis), 13 duck species, black W:H; Great crested flycatcher, EN:R; Cassin's kingbird·, LW:P; tern (Chlidonias niger), American avocet (Recurvirostra ameri­ Western kingbird, T:P ,R; Eastern kingbird, T:P ,R; Horned lark, cana), willet (Catoptrophorus semipalmatus), and Wilson's phal­ T:P; Purple martin·, L:H; Tree swallow, E:L,R; Rough-winged arope (Phalaropus tricolor). Third, an additional assemblage of swallow, T:R; Bank swallow·, L:R; Cliff swallow, T:H; Barn seven bird species breed in fresh water marshes including the swallow, T:H; Blue jay, T:P,R,H; Black-billed magpie·, L:P; yellow-headed blackbird (Xanthocephalus xanthocephalus) and five American crow, T:P,R; Black-capped chickadee, T:P,R; White­ rail and bittern species. Fourth, a distinctive assemblage of avi­ breasted nuthatch, E:R,H; House wren, T:H,R; Sedge wren·, L,P; fauna is made up of twenty-five species that breed in dry or mesic Marsh wren, T:M; Eastern bluebird, T:H,R; Mountain bluebird, prairie. Of this group, those of special interest are the long-billed WL:P; Wood thrush, N:R; American robin, T:H,R; Gray catbird, curlew (Numenius american us) , upland sandpiper (Bartramia lon­ T:P ,R; Northern mockingbird, A:H; Brown thrasher, T:P ,R; Cedar gicauda), sharp-tailed grouse (Tympanuchus phasianellus), greater waxwing·, L:R; Loggerhead shrike, T:P; European starling, T:H; prairie chicken (Tympanuchus cupido), Swainson's hawk (Buteo Bell's vireo, T:P,R; Warbling vireo, T:P,R; Red-eyed vireo, T:P,R; swainsoni), golden eagle (Aquila chrysaetos), short-eared owl (Asio Yellow warbler, T:P,R; Black-and-white warbler, EN:R; American flammeus) , burrowing owI (Athene cunicularia), and chestnut­ redstart, N:R; Ovenbird, EN:R; Common yellowthroat, T:P,R,M; collared longspur (Calcarius ornatus). Fifth, an additional feature Yellow-breasted chat, T:P ,R; Scarlet tanager·, EN:R; Northern car­ of the Sand Hills is the Niobrara River Valley, whose riparian dinal, E:H,R; Rose-breasted grosbeak, E:R; Black-headed grosbeak, vegetation provides habitats for many eastern bird species. Sixth, W:R; Blue grosbeak, T:P; Lazuli bunting·, W,R; Indigo bunting, the introduction of pine forests into the Sand Hills, now admin­ E:R; Dickcissel, T:P; Rufous-sided towhee, E:R; Chipping sparrow, istered as two National Forest units, provides coniferous forest N:H,R; Field sparrow, T:P,R; Vesper sparrow, N:P; Lark bunting, habitat. Seventh and last, but certainly not least, a crucial feature T:P; Savannah sparrow, N:P; Lark sparrow, T:P; Grasshopper spar­ of the Sand Hills for faunal conservation is the large size of the row, T:P; Song sparrow, E:L; Swamp sparrow, E:M; Chestnut­ region. It is now generally recognized that long-term species con­ collared longspur, N:P; Red-winged blackbird, T:M,P,R,; Eastern servation requires large habitat units that can accommodate large meadowlark, TL:P, Western meadowlark, T:P; Yellow-headed populations (Soule 1986). Large population sizes serve to assure blackbird, T:M,P ,R; Brown-headed cowbird, T:H,M,P ,R; Common genetic diversity and to buffer against oscillations associated with grackle, T:H,R; Orchard oriole, T:P ,R; No. (Baltimore) oriole, climatic fluctuations, predator/parasite-prey cycles, or other pe­ T:P,R; House finch·, SL,H; Pine siskin, N:F; American goldfinch, riodic perturbations. The concurrent presence of all these conser­ T:R; House sparrow, T:H vation features in a single grassland region makes the Sand Hills of special interest in North American avifaunal conservation. 64 PROCEEDINGS OF THE ELEVENTH NORTH AMERICAN PRAIRIE CONFERENCE

Invertebrate Fauna. best. And for many invertebrate species, there will prove to be no Although the invertebrates of the Sand Hills have not been extralimital populations, and the Sand Hills forms will prove to intensively investigated, some groups have received attention (Hagen be indisputable endemics. Thus, when more complete invertebrate 1970, Whitcomb et al. 1988). The strong influence of the sandy inventories are available, an increasingly large list of endemic substrate on the plant communities assures that the associated insect invertebrates can be expected. assemblages will be of special interest. This perspective can be Finally, the very large size of the Sand Hills contributes to the illustrated with some insights from our own research. diversity of its biota by permitting it to encompass geographic In a cQmparison of the cicadellid fauna of five major grassland gradients. For example in many insect groups, such as mosquitoes regions, we found the Nebraska Sand Hills assemblage to be es­ (Lunt 1987), eastern or western, or northern and southern, range pecially diverse (Whitcomb et al. 1988). Because cicadellids are limits are encountered. This situation is not limited to invertebrates; highly host specific, the underlying factors governing this diversity many plant and animal species reach one or another range limit are easily surmised. Grassland leafhopper species can be classified within the region (Jones 1964, Great Plains Flora Association as either generalists or specialists. Many generalists are actually 1986). broadly oligophagous species that confine their feeding to either grasses or forbs (Whitcomb et al. 1986 and 1987). Leafhopper Sand Hills History diversity, therefore, directly reflects the diversity of dominant, Just as an understanding of the geologic history of the Sand perennial, native grasses and forbs (Whitcomb et al. 1986). Be­ Hills region is vital to an understanding of its present-day phy­ cause the Sand Hills have recruited vegetational elements from siognomy and biota, an understanding of human colonization of surrounding prairie formations (east and west, north and south), the Sand Hills is important to considerations of its future. and have, in addition, an assortment of plant communities de­ Native American colonization. pendent on a sandy substrate, they are vegetationally rich. The There is considerable evidence for colonization of the Great cicadellid species richness that we noted is therefore a direct re­ Plains at least 11,500 YBP. Indeed, many workers believe that the flection of plant species richness. plains may have been colonized as early as 20,000 YBP. Thus, Several Sand Hills leafhoppers proved to be of special interest. early native Americans were certainly on the scene at the time of These include especially species of the genus Flexamia. Members formation of the Sand Hills in the Holocene. It is by no means of this genus are closely associated with dominant, perennial, certain that the Sand Hills were avoided by hunter-gatherers during native chloridoid grasses (Whitcomb and Hicks 1988). We hy­ periods of eolian activity, inasmuch as bison tracks occur in dune pothesized that grasses fitting this description but that were only sand dated 7,260 YBP. These tracks suggest the presence of sem­ locally dominant, and therefore regionally uncommon or rare, ipermanent water, even during dune-building episodes (Holen, could be hosts for undescribed Flexamia species. Two Sand Hills 1989). grasses appeared to fit this profile, both dominants of the blowout In the Paleo-Indian Period, at the close of Wisconsinan glacia­ association; sand muhly [Muhlenbergia pungens Thurb.) and blow­ tion, Native Americans hunted mammoth and mastodon. After out grass, [Redfieldiaflexuosa (Thurb.) Vasey]. It turned out that extirpation of these prehistoric mammals, bison probably served each was colonized by an undescribed Flexamia species. Flexamia as the main prey for the hunters. Other species that were hunted celata was associated with blowout grass, and F. arenicola with included elk, deer, antelope, and smaller mammals. Waterfowl sand mUhly. These species were recently described by Lowry and and fish were also probably hunted. Mass bison kills have been Blocker (1987). The type locality for each is a research natural dated between 8,000 and 10,000 YBP. Steep-sided gullies were area of Crescent Lake National Wildlife Refuge in the western used as traps into which the bison were driven. Also, prehistoric Sand Hills. agriculture may have been practiced on stream terraces and around At first we thought that these new species would tum out to be some of the Sand Hills lakes. endemics of the Nebraska Sand Hills. Further search, however, There is abundant evident of agriculture in the Archaic period, turned up other populations of these species (Whitcomb and Hicks 7,000-2,000 YBP. For example, many grinding stones for pro­ 1988). In each case, however, the male genitalia of the extralimital cessing seeds have been recovered. Many artifacts from this period popUlations show evidence of divergence from the Sand Hills document extensive use of the Sand Hills for hunting. populations. The case of F. arenicola is especially interesting, in In the Woodland period (2,000-1,000 YBP), ceramic vessels that the recently discovered population (Anasazi form) in the Four were used indicating a more sedentary lifestyle than that of the Comers area (Arizona-New Mexico-Utah-Colorado) is clearly dis­ earlier hunter-gatherers. Pottery from this period is common along junct from the Nebraska population. The host, sand mulhy, is itself Sand Hills lakes and streams. Squash and beans were among the essentially disjunct, blocked on the northwest face of the Colorado crops that were cultivated. Some maize was also grown late in the Rockies by a combination of the Uinta Mountains and the dry period. Agropyron steppe of Wyoming and northern Colorado, and on the After the Woodland period, 500-1000 YBP, Central Plains Tra­ east by nons and areas of Colorado and New Mexico (Whitcomb dition and Initial Coalescent peoples (thought to be ancestral to and Hicks 1988). Male genitalia of the Four Comers population the Pawnee and Arikara) inhabited the plains, practicing a mixed are invariably broken, an event that presumably occurs during economy of com, beans, and squash, in addition to hunting. copulation. Therefore, it appears that the process of genetic di­ In all, there is only limited evidence for permanent occupation vergence between the two populations has begun. From a con­ of the Sand Hills during the Holocene. It is clear, however, that servation point of view, the important feature of the Nebraska Sand a number of the tribes that resided around the periphery of the Hills population is that it is in little danger of extinction since its Sand Hills used the region for seasonal hunting (Holen 1989). For host reservoir is very large, and the regional population is divided example, the Plains Apache, although essentially southwestern, into a large number of subpopulations, permitting "hedging" in are well documented archaeologically in the Sand Hills, where the event of regional catastrophe. Populations of the Anasazi form they must have competed with the Pawnee for bison-hunting range. may be stressed by increasing aridity in the Four Comers region. The Comanche appear to have been short-term occupants in the For all of its sand biota, the Sand Hills provide an extent of 1700s. habitat that is large enough to support viable populations. Espe­ In historic times, a wide array of tribes utilized the Sand Hills. cially because episodes of eolian activity appear to be more fre­ From 1540 to 1740, a mixed economy based on horticulture and quent than once supposed (Ahlbrandt et al. 1983, Swinehart 1989), hunting was practiced in the eastern plains. Farther west, other extinction rates in small sand regions may prove to be high. Clearly, groups were predominantly hunter-gatherers, following a seasonal from all considerations of classical island biogeography (Mac­ cycle in which bison were the main food supply. Both types of Arthur and Wilson 1967), the larg~st sand reserve is surely the economy, however, led to use of the Sand Hills for hunting. NEBRASKA SAND HILLS: THE LAST PRAIRIE 65

A 1718 map shows 12 villages of the Skidi-band Pawnee on east of the Sand Hills could often be homesteaded successfully, the Loup River and another group of 12 villages that represented the Sand Hills, even more than the semiarid lands to the west, the Grand band of Pawnees (Tucker 1942). Skidi hunting territory were not amenable to settlement of a mere 65 ha. appears to have been from the Platte River north into the Sand Encouraged by the construction of railroads, floods of settlers Hills to the Dismal River. Some of the eastern Sand Hills were arrived in the plains in the 1880s to take up either farming or, to hunted by the Omaha (Holen 1989). be lured by the open range in the public domain, cattle ranching. On the northern edge, the Ponca hunted west along the Niobrara And, with vast acreages of public land available, the cattle business River and ventured south into the hills. But if they went too far could be immensely profitable. For example, the cattle enterprise they encountered Brule, Oglala, or Cheyenne. Some areas of the in 1895 in the northern Sand Hills was estimated to have yielded central Sand Hills (e.g., Shell Creek north to the Niobrara), may $2,000,000 (Richards 1980). have been disputed by the Omaha and Cheyenne, as well as by By the tum of the century, Sand Hills ranching had become a the Pawnee and Ponca. Certain Sioux tribes also utilized the hills; large-scale operation. For example, on a large ranch two or three by the 1830s the Brule Sioux were contesting the hunting grounds windmills were established at each water station, each fitted with of the Pawnee and Omaha. a 7.5-10.0 cm pump operated by a 3.7 m wooden windmill. Water from these mills flowed into reservoirs 6-9 m in diameter. The European colonization. stations cost as much as $1,000 each; costs such as these were, European colonists were slow to discover the Sand Hills. of course, beyond the means of small operators. An indication of The region was known to early settlers as the "Sand Hills Desert" the size of a large operation can be obtained by measuring some and was studiously avoided by early travellers. It was, in the words of the tasks; in July, the Spade, one ranch operation, cut 15,000 of B. Richards . , 'avoIded as no other part of the cattle country. tonnes of hay and plowed 644 km of fireguards. By the early The awe of this desert was widespread and real. Men 1900s, the Spade was the largest cattle company in Nebraska, had been known to venture into the region, lose their running between 20,000 and 40,000 head. way and never be seen again. The hills were covered Fire was a real threat, especially in the fall and winter, when with a rather long grass [presumably prairie sandreed the grasses became tinder dry. Fires, if not extinguished, burned [Calamovilfa longifolia (Hook) Scribn.]; all hills looked over large areas, destroying range and winter feed. For this reason, alike; there were few landmarks; and water was uncer­ large ranches like the Spade (Richards 1980) employed crews that tain, often alkaline." plowed parallel fireguards that completely encircled their range. The grass between the guards was burned between August and B. Richards J r., 1980 October. The value of the region was apparently first discovered by cow­ Fire, however, was not the only natural threat to ranching in the boys of the N Bar Ranch, which was located 80 km east of Chadron Sand Hills. Severe losses due to climatic variations, such as those on the Niobrara River (Figure 3). During the winter, the N Bar experienced in the droughts and severe winters of 1885-87 made deployed line riders along the northern edge of the Sand Hills to it clear that planning for winter range, good water, and hay for prevent cattle wandering into them. In March 1879, however, an feed during winter snows were essential for a cattle operation. It intense blizzard forced the line riders to seek shelter for survival, was impossible to manage in this way without fencing. For ex­ and some 6,000 N bar cattle drifted into the hills. An expedition ample, it was necessary to protect lower hay meadows from un­ was organized to rescue the lost cattle, and the N bar wagon headed timely grazing. Under an open range system, the cattle grazed hay into the hills on April 15. meadows preferentially in the summer. These hay meadows and As told by Jim Dahlman, who later became mayor of Omaha, winter pastures needed to be fenced and protected from grazing as they entered the hills, the members of the expedition began to and fire during the summer months. In the winter, the cattle were find native cattle: given access to the protected pastures and supplied with hay during winter snows. "as fat as any ever brought out of a feed lot; mavericks But throughout the semiarid grasslands, and especially in the [unbranded] from one to four years old. We could hardly Sand Hills, it was virtually impossible for stockmen, within the believe our eyes . . . Remember these cattle had no feed law, to obtain outright ownership of enough lands for their needs. except native grass, and this was the month of April, "It took much scheming, scrambling, and perjury to assemble the after a terrific winter." acreage necessary for a sound ranching operation" (Larson 1965). Jim Dahlman, 1927 As a result of the fencing controversy, legislators from Great Plains states introduced legislation in 1901 under which federal The expedition was a long one, and provisions ran low. Camping lands adjacent to ranch holdings could be leased. But President near a lake one day, the party had a dinner consisting solely of Theodore Roosevelt, although generally sympathetic to conser­ bean soup. In honor of that dinner, the lake was named Bean Soup vation interests and no stranger to the plains, was unsympathetic Lake. In all, the expedition, which lasted five weeks, netted 8,000 to the fences. In his administration, the fencing act of 1885 was bar N cattle and 1,000 head of "natives" that had been there for to be enforced: "Gentleman, the fences must come down." And years (Dahlman 1927). It was this expedition that established the in 1904, Congress passed the Kinkaid Act, which,. in 37 counties Sand Hills as exceptional cattle range. of western Nebraska (Figure 3), increased the size of homestead At the time of their "discovery," the Sand Hills were almost tracts from 65 to 260 ha. Unfortunately, this act combined 15 totally in the public domain. From the time of the American Rev­ counties that were predominantly Sand Hills with 22 others of olution, disposition of western lands had been an important issue. greater farming potential. Whereas some semiarid lands could be For many years after the Revolution, proceeds from land sales farmed in units of 260 ha, few Sand Hill tracts of that size were were used to reduce the national debt. Speculation in western lands "proved up." Efforts to liberalize the law to permit land to pass became a common business enterprise. Land was cheap. For ex­ more readily into private ownership were made. One was an ample, under the Preemption Act of 1841, 65 ha (160 A) could amendment to the Kinkaid Act by which 194 ha (480 acre) isolated be purchased for $3.09/ha ($1.25/A). At such prices, most arable or disconnected tracts could be sold. In 1912, sale was authorized land east of the Mississippi River passed readily into private own­ of 65 ha tracts "the greater part of which is mountainous or too ership. To encourage westward migration, President Lincoln in rough for cultivation." In the same year, the time required to gain 1862 signed the Homestead Act, under which settlers were given title under the Kinkaid Act was reduced from five to three years. title to tracts of 65 ha of surveyed public domain if they cultivated By all these devices, the public domain of the Sand Hills eventually the land and lived on it for five years. However, while arable land devolved into private ownership. 66 PROCEEDINGS OF THE ELEVENTH NORTH AMERICAN PRAIRIE CONFERENCE

But the process was made no easier by the failure of Congress Biotic heritage. to devise legislation that was appropriate for the Sand Hills. As A compelling case for conservation of Sand Hills grasslands can stated by Richards (1980): "The argument by Sand Hill ranchers, be made of the basis of biotic conservation. Because the Sand tirelessly reiterated, that their area was unique and should be han­ Hills are the largest sand dune area in the Western hemisphere and dled as a grasslands unit ... convinced few people in Washing­ are one of the largest stabilized dune areas in the world (Bleed ton." and Flowerday 1989), they are globally significant as a refugium Today's ranches, the product of numerous consolidations, are, for all of the plant and invertebrate species - whether or not their for the most part, large enough to engage in the management biologies are currently known - that evolved with the sand ~rairies practices devised by the earlier stockmen. In the east, some ranches of the Pleistocene and Holocene. Also, because the Sand HIlls are . of about 500 ha are proving to be sustainable, whereas in the west, the last prairie, they are of significance for many prairie animal average sizes are 1,600-2,400 ha (Miller 1989). But now, as al­ or plant species that have vanished from, or are threatened or ways, the secret to effective stewardship of Sand Hills land is endangered in, prairie formations elsewhere. respect for the ecological forces that created the grassland and that The conservation significance of the Sand Hills has not gone are responsible for maintaining it. ' completely unnoticed. Three national wildlife refuges have been established in the region; Valentine (28,942 ha), Crescent Lake Grassland conservation. (18,616 ha), and Fort Niobrara (7,739 ha). Also, the Nature Con­ In general, interest in grassland conservation in the United States servancy has acquired two preserves; the Niobrara Valley Preserve is geographically uneven (Whitcomb 1986). Predictably, greatest (21,853 ha) (Harrison 1980) and Arapaho Prairie (780 ha). How­ concern for losses of prairie come from states in which present­ ever, given the relatively low carrying capacity of Sand Hills soils, day destruction is nearly complete. These are, essentially, states the large acreages in these preserves are deceptive. The carrying such as Minnesota, Wisconsin, Iowa, Illinois, and Missouri that capacity of dry Sand Hills prairie, with its thin topsoil ~nd eas~ly originally had extensive savannas or forest-prairie mosaics. Con­ erodible soils, may be no more than a tenth of that of ncher SOlIs servation groups in these states are very active and in some cases of, for example, eastern deciduous forest. (e.g., Missouri) have managed to salvage small but significant The small size of the Sand Hills prairie preserves seems anom­ preserve areas. However, in many instances, prairie destruction alous when contrasted with its planted forests (Hunt 1965, Schmidt has gone too far, and restoration, rather than conservation, is being 1986). These units, established as experiments in type conversion attempted. Unfortunately, even the botanical elements of prairie of prairie to forest, occupy more than 81,000 ha. By this measure, cannot be wholly reconstructed, and faunal restoration is totally more effort has been made to establish "reserves" that destroy hopeless. prairie by replacing it with an artificial fire- and drought-sensitive It would certainly be helpful if states with an existing prairie formation than to preserve the native vegetational communities. inventory were to give grassland conservation the priority status Important though they may be, the existing prairie reserves are it deserves. The fate of tall-grass prairie rests today on a few not large enough to be self-sufficient; they are dependent on good remnants that are managed as rangeland or hay meadows. Unfor­ management of surrounding range. As a result, their value would tunately, because these tracts are almost exclusively in private be fatally compromised if the Sand Hills around them were to be ownership, they will eventually be subjected to some or many of diverted to nongrassland uses. But today these grasslands stand the same pressures that have already destroyed most prairie. In intact. Guarantors, in a sense, of the preserves. Together, public such regions, it is surely desirable to sequester prairie reserves. I and private lands function as a complete prairie ecosystem, not a wish to stress, however, that landowner participation should be a mere remnant of one. The long-billed curlews, avocets, and phal­ vital part of this process. In many instances, the public owes aropes that we see in the refuges are in fact members of regional landowners a deep debt of gratitude, since retention of their lands populations whose long-term existence requires not only the ref­ as grassland has involved personal decisions that fully recognized uges but the privately owned grasslands that surround them. the intrinsic value of the land as natural grassland. In semiarid grasslands west of the Sand Hills, disappearance of Landscape heritage. native communities is less imminent, but many problems exist nonetheless. For example, there are many controversial issues "The Sand Hills are beautiful today, soft and green and dotted with flowers .... You feel that you are not tres­ regarding optimal land use. In much of the semiarid west and passing when you stroll over the hills or lie at length on southwest, grasslands are under public ownership, in many cases the sand, watching the shadows of the clouds drift over by the USDA Forest Service or Bureau of Land Management. the dimpled hills. ' , Although personnel of these agencies are almost unanimously con­ cerned about proper management, they are constrained by the Joe Wing, Breeders Gazette, July, 1904 definition of their missions. The missions of these agencies, par­ There are various fundamental criteria by which a society de­ ticularly concerning the balance between conservation and ~x­ serves to be judged. One of these is the degree of respect that it ploitation, is a proper subject for public debat~. The west~rn thl~d accords to its natural heritage. As rich and deserving as is the case of the nation is a confetti-like assortment of tmy vegetatIOn umts for conservation of the Sand Hills on biotic grounds, unquestion­ defined by climatic and elevational barriers and the topographies ably the greatest case lies in their landscape itself. of mountain ranges, valleys, and river systems (KUchler .1985). Research on many plant or insect taxa indicates an exceptIOnally In the early years of park and forest planning in the United States, there was a clear appreciation of the value of bigness. In high species richness in this part of the United States, particularly his tenure as President, Theodore Roosevelt ensured the seques­ in the southwest, where extinctions attributable to glacial cycles tering of 61 million ha of public domain into the National Forest have been minimized by altitudinal migrations of communities. System. As exploitative as the free enterprise system was of the Preserve design in the face of such complexity is at present difficult environment, means were found to create parks of the size of or impossible (Whitcomb 1986). Rather, it is reasonable to hope Yellowstone (about 900,000 ha), Yosemite (about 300,000 ha), that the bulk of the semiarid lands will be forever held in public and Grand Canyon (about 500,000 ha). There can be no question, ownership and managed for the common good, balancing resource in contemplating the diverse natural features of these parks, that needs with responsible management of biological and historical they are the work of an ambitious nation that placed great value resources. in its finest and unique natural features. But scenic wonders not­ withstanding, the very size of these parks may be their most im­ portant characteristic. NEBRASKA SAND HILLS: THE LAST PRAIRIE 67

The success of such parks could never have been achieved had LITERATURE CITED they been niggardly in inception. Had the park process preserved the equivalent of Yellowstone Park in pieces (a geyser here, a hot Ahlbrandt, T. S. 1973. Sand dunes, geomorphology and geology, spring there, a montane lake here, and a waterfall there) the cu­ Killpecker Creek Area, Northern Sweetwater County, Wyo­ mulative impact of the separate pieces would not add up to a ming. Doctor of Philosophy Thesis, University of Wyoming, scintilla of the Yellowstone experience enjoyed by today's park Laramie. visitors. Or imagine preservation of a "representative section" of Ahlbrandt, T.S., and S.G. Fryberger. 1980. Eolian deposits in the the Grand Canyon. Nebraska Sand Hills. United States Geological Survey Profes­ In what we choose to conserve, we make an important statement sional Paper 1120A: 1-24. about space. From the time of European settlement of the New Ahlbrandt, T.S, J.B. Swinehart, and D.G. Maroney. 1983. The World, possibility has been an open-ended process, and it has been dynamic Holocene dune fields of the Great Plains and Rocky symbolized in an important way in the relationship of Americans Mountain basins, USA. Pages 379-406. In M.E. Brookfield and with unoccupied land. In a great nation, there is a national need T.S. Ahlbrandt (eds.). Eolian sediments and processes, devel­ for vastness. opments in sedimentology, Volume 38. Elsevier Science Pub­ Unfortunately, we have been grossly negligent in our planning lishers, Amsterdam, The Netherlands. for prairie space. Of the millions of km2 of Pre-Columbian tallgrass American Ornithologists' Union. 1983. Checklist of North Amer­ and transitional prairie (approximately 550,000 km2 exclusive of ican birds. 6th Edition. the Nebraska Sand Hills) and Oak savanna/deciduous forest-prairie Barnes, P.W. 1980. Water relations and distributions of several mosaic (about 460,000 km2), none has been saved in National Park dominant grasses in a Nebraska Sand Hills Prairie. Master of or National Grassland, and essentially none in National Forest. Science Thesis. University of Nebraska, Lincoln. The neglect of prairie grassland in our national aspiration for space Barnes, P.W., and A.T. Harrison. 1982. Species distribution and represents a glaring and unacceptable omission. The national need community organization in a Nebraska Sand Hills prairie as for prairie space is supplied today by the private, not the public influenced by plant/soil water relationships. Oecologia 52: 192- sector, in the Nebraska Sand Hills. 201. Barnes, P.W., and S.P. Heinisch. 1984. Vegetation patterns in CONCLUSIONS relation to topography and edaphic variation in Nebraska Sand Hills prairie. Prairie Naturalist 16:145-158. So the Nebraska Sand Hills Prairie today, in the vast majority Barry, R.G. 1983. Climatic environment of the Great Plains, past (90%) of grassland that remains unplowed (Miller 1989), retains and present. Transactions of the Nebraska Academy of Sciences its character as native grassland. Preservation of the region has 11 :45-55. been achieved not through the park process, but as a result of Bentall, R. 1989. Streams. Pages 93-114. In A. Bleed and C. natural economic forces. As reforestation of the Sand Hills was Flowerday (eds.). An atlas of the Sand Hills. University of once a dream (Hunt 1965), so the concept of intensive agricul­ Nebraska Conservation and Survey Division Resource Atlas ture has more recently proved again to be unsustainable, even in Number 5. the short term. The Conservation Reserve Program is the most Bleed, A. 1989. Groundwater. Pages 67-92. In A.Bleed and C. recent vehicle by which incentives for grassland maintenance are Flowerday (eds.). An atlas of the Sand Hills. University of being reinforced. In the Sand Hills region, maintenance of native Nebraska Conservation and Survey Division Resource Atlas grassland has proven to be the best economic alternative. Number 5. I argue that Sand Hills landowners have contributed to the nation Bleed, A., and C. Flowerday (eds.). 1989. An atlas of the Sand a more-or-Iess unrecognized public good. These landowners are Hills. University of Nebraska Conservation and Survey Division good stewards of the land not only because it is in their economic Resource Atlas Number 5. interest but also because they know the land and its limitations Bleed, A., and M. Ginsberg. 1989. Lakes and wetlands. Pages (Stubbendieck 1989). They care for the land as no casual visitor 115-122. In A. Bleed and C. Flowerday (eds.). An atlas of the or short-term manager could (Madson 1978). In so doing, they Sand Hills. University of Nebraska Conservation and Survey have regularly performed many of the vital functions of the park Division Resource Atlas Number 5. process; they have maintained, and are continuing to maintain, an Bliss, Q.P. and S. Schainost. 1973. Niobrara River stream inven­ entire vegetational region in an essentially pre-Columbian condi­ tory report. Nebraska Game and Parks Commission, Lincoln. tion. It is not clear that this function has been recognized even in Bragg, T.B. 1978. Effects of burning, cattle grazing and topog­ verbal terms, let alone in the structuring of economic incentives. raphy on vegetation of the choppy sands range site in the Ne­ In the Sand Hills, history strongly suggests that optimal long­ braska Sand Hills Prairie. Pages 248-253. In D.N. Hyder (ed.). term public and private land use may be one and the same. Is it Proceedings of the First International Rangeland Congress, Den­ not possible that means can be found, by adjustments in public or ver. private policy, to encourage this historic silent partnership between Bradbury, J.P. 1980. Late Quaternary vegetation history of the wise land managers and a nation made richer by the treasure that Central Great Plains and its relationship to eolian processes in they have preserved? It is my hope that the future may see a new the Nebraska Sand Hills. United States Geological Survey direction in conservation, one that seeks specific means to stabilize Professional Paper 1120C:25-36. desirable land use patterns by encouraging wise private steward­ Brinegar, R.E., and F.D. Keim. 1942. The relations of vegetative ship. Such an approach would pay rich dividends in the Nebraska composition and cattle grazing on Nebraska range land. Uni­ Sand Hills. versity of Nebraska Agricultural Experiment Station Research Bulletin 123. ACKNOWLEDGEMENTS Burzlaff, D.F. 1962. A soil and vegetation inventory and analysis of three Nebraska Sand Hills range sites. University of Nebraska I gratefully acknowledge discussions of Sand Hill geology with Agricultural Experiment Station Research Bulletin 206. T. S. Ahlbrandt that improved the paper immeasurably. Comments Dahlman, J. 1927. Recollections of cowboy life in western Ne­ of an anonymous reviewer on an earlier draft of the manuscript braska. Nebraska History Magazine 10:335-339. were also extremely valuable. I thank my wife, Judith B. Leach, Fredlund, G.G., and P.J. Jaumann. 1987. Late Quaternary paleo­ for editing several versions of the manuscript. Responsibility for logical and paleobotanical records from the central Great Plains. errors remaining after such assistance remains, however, with the Pages 167-178. In W.C. Johnson (ed.). Quaternary environ­ author. ments of Kansas. Kansas Geological Survey Guidebook Series 5. 68 PROCEEDINGS OF THE ELEVENTH NORTH AMERICAN PRAIRIE CONFERENCE

Freeman, P. 1989a. Amphibians and reptiles. Pages 157-160. In Lowry, J.E., and H.D. Blocker. 1987. Two new species of Flex­ A. Bleed and e. Flowerday (eds.). An atlas of the Sand Hills. amia from the Nebraska Sand Hills (Homoptera: Cicadelli­ University of Nebraska Conservation and Survey Division Re­ dae:Deltocephalinae). Proceed-ings of the Entomological Society source Atlas Number 5. of Washington 89:57-60. Freeman, P. 1989b. Mammals. Pages 181-188. In A. Bleed and Lugn, A.L. 1935. The Pleistocene geology of Nebraska. Univer­ C. Flowerday (eds.). An atlas of the Sand Hills. University of sity of Nebraska Conservation and Survey Division Bulletin Nebraska Conservation and Survey Division Resource Atlas Number 10, Second Series. Number 5. Lunt, S.R. 1987. North American mosquito species with geo­ Frolik, A.L., and W.O. Shepherd. 1940. Vegetative composition graphical distribution limits in Nebraska. Nebraska Academy of and grazing capacity of a typical area of Nebraska Sand Hill Sciences Annual Meeting 97: 18-19. rangeland. University of Nebraska Agricultural Experiment Sta­ MacArthur, R., and E.O. Wilson. 1967. The theory of island tion Research Bulletin 117. biogeography. Princeton University Press, Princeton, New Jer­ Great Plains Flora Association. 1986. Flora of the Great Plains. sey. University Press of Kansas, Lawrence. Madson, J. 1978. Land of long sunsets. National Geographic Hagen, A.F. 1970. An annotated list of grasshoppers (Orthoptera, 154:493-517. Acrididae) from the eleven Panhandle counties of Nebraska. May, D.W., and S.R. Holen. 1985. A chronology of Holocene Nebraska Agricultural Experiment Station Research Bulletin 238. erosion and sedimentation in the South Loup Valley, Nebraska. Harrison, A.T. 1980. The Niobrara Valley Preserve: Its biogeo­ Geological Perspectives 56:8-12. graphical importance and description of its biotic communities. Miller, S.M. 1989. Land development and use. Pages 207-226. Report to the Nature Conservancy. Minneapolis. In A. Bleed and C. Flowerday (eds.). An atlas of the Sand Hills. Heinisch, S.P. 1981. Water allocation and rooting morphology of University of Nebraska Conservation and Survey Division Re­ two Bouteloua species in relation to their distribution patterns source Atlas Number 5. in the Nebraska Sand Hills. Master of Science Thesis. University Molhoff, W.J. 1985. The Nebraska breeding bird atlas project. of Nebraska, Lincoln. Nebraska Academy of Sciences Annual Meeting 94:23. Holen, S.R. 1989. Anthropology: The native american occupation Muhs, D. 1985. Age and paleoclimatic significance of Holocene ofthe Sand Hills. Pages 189-205. In A. Bleed and e. Flowerday sand dunes in northeastern Colorado. Annals of the Association (eds.). An atlas of the Sand Hills. University of Nebraska Con­ of American Geographers 75:566-582. servation and Survey Division Resource Atlas Number 5. Pool, R.J. 1914. A study of the vegetation of the Sand Hills of Hrabik, R.A. 1989. Fishes. Pages 143-156. In A. Bleed and e. Nebraska. Minnesota Botanical Studies 4:189-312. Flowerday (eds.). An atlas of the Sand Hills. University of Pound, R., and F.E. Clements. 1900. The phytogeography of Nebraska Conservation and Survey Division Resource Atlas Nebraska. General survey. University of Nebraska Botanical Number 5. Survey, Lincoln. Hunt, J.e. 1965. The forest than men made. Parts I and II. Amer­ Ramaley, F. 1939. Sand Hill vegetation of northeastern Colorado. ican Forests. Ecological Monographs 9: 1-51. Jones, J.K., Jr. 1964. Distribution and taxonomy of the mammals Raup, H.Y., and G.W. Argus. 1982. The Lake Athabasca sand of Nebraska. University of Kansas Publications of the Museum dunes of northern Saskatchewan and Alberta, Canada. 1. The of Natural History 16: 1-356. land and vegetation. Canadian Museum of Natural Sciences Kaul, R. 1989. Plants. Pages 127-142. In A. Bleed and e. Flow­ Publications in Botany 12: 1-96. erday (eds.). An atlas of the Sand Hills. University of Nebraska Richards, B., Jr. 1980. Bartlett Richards: Nebraska Sand Hills Conservation and Survey Division Resource Atlas Number 5. cattleman. Nebraska State Historical Society, Lincoln. Kaul, R.B., and S.B. Rolfsmaier. 1987. The characteristics and Schmidt, TL. 1986. Forestland resources of the Nebraska Sand phytogeography of the flora of Nine-Mile Prairie, a western tall­ Hills. In TD. Wardle (ed.). University of Nebraska and Ne­ grass prairie in Nebraska. Transactions of the Nebraska Acad­ braska Forest Service, Lincoln. emy of Sciences. XV:23-35. Smith, H.T.U. 1965. Dune morphology and chronology in central Kaul, R.B., G.E. Kantak, and S.P. Churchill. 1988. The Niobrara and western Nebraska. Journal of Geology 73:557-578. River Valley, a postglacial migration corridor and refugium of Soule, M. (ed.). 1986. Conservation biology. Sinauer Associates forest plants and animals in the grasslands of central North Incorporated, Sunderland, Massachusetts. America. Botanical Review 54:44-81. Steinauer, E.A., and T.B. Bragg. 1987. Ponderosa pine (Pinus Keech, e.F., and R. Bentall. 1978. Dunes on the plains, the Sand ponderosa) invasion of the Nebraska Sand Hills Prairie. Amer­ Hills region of Nebraska. University of Nebraska Conservation ican Midland Naturalist 118:358-365. and Survey Division Resource Report Number 4. Stubbendieck, J. 1989. Range management. Pages 222-233. In A. Kuchler, A.W. 1964. Potential natural vegetation of the conter­ Bleed and C. Flowerday (eds.). An atlas of the Sand Hills. minous United States. Special Publications, American Geo­ University of Nebraska Conservation and Survey Division Re­ graphical Society, Washington, D.e. source Atlas Number 5. Kuchler, A.W. 1985. Potential natural vegetation. National Atlas Sutherland, D.M. 1984. Vegetative key to grasses of the sand hills of the United States of America. Department of the Interior, region of Nebraska. Transactions of the Nebraska Academy of U.S. Geological Survey, Reston, Virginia. Sciences 12:23-60. Labedz, T.E. 1989. Birds. Pages 161-180. In A. Bleed and e. Sylvester, D.D. 1957. Response of Sand Hill vegetation to deferred Flowerday (eds.). An atlas of the Sand Hills. University of grazing. Journal of Range Management 10:255-292. Nebraska Conservation and Survey Division Resource Atlas Swinehart, J.B. 1989. Wind-blown deposits. Pages 43-56. In A. Number 5. Bleed and C. Flowerday (eds.). An atlas of the Sand Hills. Larson, TA. 1965. History of Wyoming. University of Nebraska University of Nebraska Conservation and Survey Division Re­ Press, Lincoln. source Atlas Number 5. Lewis, D.T 1989. Origin of Sand Hills soils. Page 57. In A. Bleed Swinehart, J.B., and R.F. Diffendal, Jr. 1989. Geology of pre­ and e. Flowerday (eds.). An atlas of the Sand Hills. University dune strata. Pages 29-42. In A. Bleed and C. Flowerday (eds.). of Nebraska Conservation and Survey Division Resource Atlas An atlas of the Sand Hills. University of Nebraska Conservation Number 5. and Survey Division Resource Atlas Number 5. NEBRASKA SAND HIllS: THE LAST PRAIRIE 69

Tolstead, W.L. 1942. Vegetation of the northern part of Cherry Whitcomb, R.F., J. Kramer, M.E. Coan, and A.L. Hicks. 1986. County, Nebraska. Ecological Monographs 12:255-292. Ecology and evolution ofleafhopper-grass relationships in North Tucker, S.J. 1942. Indian villages of the Illinois Country. Scientific American prairies, savanna, and ecotonal biomes. Current Top­ Papers, Atlas, Volume 2, Part 1. Illinois State Museum, Spring­ ics in Vector Research 4:125-182. field. Whitcomb, R.F., A.L. Hicks, H.D. Blocker, and J.P. Kramer. Voorhies, M.R., and R.G. Cormer. 1985. Small mammals with 1988. Host specificity: a major mechanism enhancing insect boreal affinities in Late Pleistocene (Rancholabrean) deposits diversity in grasslands. Paper 11.06In A. Davis and G. Stanford of Eastern and Central Nebraska. Pages 125-141. In W. Dort, (eds.). Proceedings of the Tenth North American Prairie Con­ Jr. (ed.). TER-QUA Symposium Series: Institute for Tertiary­ ference, Denton, Texas. Quaternary Studies. Nebraska Academy of Sciences. Wilhite, D.A., and K.G. Hubbard. 1989. Climate. Pages 17-28. Weaver, J.E. 1965. Native vegetation of Nebraska. University of In A. Bleed and C. Flowerday (eds.). An atlas of the Sand Hills. Nebraska Press, Lincoln. University of Nebraska Conservation and Survey Division Re­ Wells, P. V. 1983. Late Quaternary vegetation of the Great Plains. source Atlas Number Transactions of the Nebraska Academy of Sciences XI:83-89. Wilson, I.G. 1973. Ergs. Sedimentary Geology 10:77-106. Whitcomb, R.F. 1986. North American forests and grasslands: Wolfe, C.W. 1973. Effects of fire on a Sand Hills grassland en­ Biotic conservation. Pages 163-176. In D.A. Saunders, G.W. vironment. Proceedings of the Tall Timbers Fire Ecology Con­ Arnold, A.A. Burbridge, and A.J.M. Hopkins (eds.). Nature ference 12:241-255. conservation: The role of remnants of native vegetation. Surrey Wolfe, C. W. 1984. Physical characteristics of the Sand Hills: Wet­ Beatty and Sons, Sydney. lands, fisheries and wildlife. Pages 54-61. In The Sand Hills of Whitcomb, R.F., and A.L. Hicks. 1988. Genus Flexamia: New Nebraska - Yesterday, Today, and Tomorrow. Proceedings of species, phylogeny, and ecology. Great Basin Naturalist Mem­ the University of Nebraska Water Resources Seminar Series. oirs 12:224-323. Whitcomb, R.F., A.L. Hicks, D.E. Lynn, K. Allred, and H.D. Blocker. 1987. Geographic variation in host relationships of leafhoppers (Homoptera:Cicadellidae) in North American grass­ lands. Pages 293-325. In M.R. Wilson and L.R. Nault (eds.). Proceedings of the 2nd International Workshop on Leafhoppers and Planthoppers of Economic Importance. Commonwealth In­ stitute of Entomology, London.